Dr. Dobb's is part of the Informa Tech Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them. Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

Channels ▼


Prefer Futures to Baked-In "Async APIs"

Let's say you have an existing synchronous API function:

// Example 1: Original synchronous API
// that could take a long time to execute
// (to compute, to wait for disk/web, etc.)
RetType DoSomething(
  InParameters ins,
  OutParameters outs

Because DoSomething could take a long time to execute (whether it keeps a CPU core busy or not), and might be independent of other work the caller is doing, naturally the caller might want to execute DoSomething asynchronously. For example, consider calling code like this:

// Example 1, continued:
// Sample calling code
void CallerMethod() {
  // …

  result = DoSomething( this, that, outTheOther );

  // These could also take a long time

  // … now use result and outOther …

If OtherWork and MoreOtherWork don't depend on the value of result or other side effects of DoSomething, and if they can correctly run concurrently with DoSomething because they don't conflict by using the same data or resources, then it could be useful to execute DoSomething concurrently with OtherWork/MoreOtherWork.

The question is, how should we enable that? There is a simple and correct answer, but because many interfaces have opted for a more complex answer let's consider that one first.

Related Reading

More Insights

Currently we allow the following HTML tags in comments:

Single tags

These tags can be used alone and don't need an ending tag.

<br> Defines a single line break

<hr> Defines a horizontal line

Matching tags

These require an ending tag - e.g. <i>italic text</i>

<a> Defines an anchor

<b> Defines bold text

<big> Defines big text

<blockquote> Defines a long quotation

<caption> Defines a table caption

<cite> Defines a citation

<code> Defines computer code text

<em> Defines emphasized text

<fieldset> Defines a border around elements in a form

<h1> This is heading 1

<h2> This is heading 2

<h3> This is heading 3

<h4> This is heading 4

<h5> This is heading 5

<h6> This is heading 6

<i> Defines italic text

<p> Defines a paragraph

<pre> Defines preformatted text

<q> Defines a short quotation

<samp> Defines sample computer code text

<small> Defines small text

<span> Defines a section in a document

<s> Defines strikethrough text

<strike> Defines strikethrough text

<strong> Defines strong text

<sub> Defines subscripted text

<sup> Defines superscripted text

<u> Defines underlined text

Dr. Dobb's encourages readers to engage in spirited, healthy debate, including taking us to task. However, Dr. Dobb's moderates all comments posted to our site, and reserves the right to modify or remove any content that it determines to be derogatory, offensive, inflammatory, vulgar, irrelevant/off-topic, racist or obvious marketing or spam. Dr. Dobb's further reserves the right to disable the profile of any commenter participating in said activities.

Disqus Tips To upload an avatar photo, first complete your Disqus profile. | View the list of supported HTML tags you can use to style comments. | Please read our commenting policy.